CHANGE OF BIOLOGICAL-ACTIVITIES OF (1-]3)-BETA-D-GLUCAN FROM GRIFOLA-FRONDOSA UPON MOLECULAR-WEIGHT REDUCTION BY HEAT-TREATMENT

Changes of biological activities manifested by (l->6)-branched (l->3)-β-D-glucans of various molecular weights obtained by heat treatment of the corresponding intact β-glucan at 150 °C (HD-LE) were examined. The activities assessed in this study were as follows: an antitumor activity, activation of alternative complement pathway, glucose consumption by macrophages, macrophage-mediated lysosomal enzyme activity in culture supernatant and cell lysate, interleukin-1 (IL-1) activity, and adjuvant activity. HD-LE could be classified into three groups: 1) HD-LE 0h (MW 800000) which activated all of the biological activities tested, 2) HD-LE 0.5 and 3h (MW 250000 and 21000) which lacked or exhibited low levels of activities such as activation of alternative complement pathway and lysosomal enzyme secretion, 3) HD-LE 6h (MW 6400) which only activated glucose consumption and synthesis of lysosomal enzyme. These results suggest that an antitumor glucan is not always a multiple enhancer of host defense mechanisms and that a large molecular weight is required to augment multiple immunological activities. © 1990, The Pharmaceutical Society of Japan. All rights reserved.